Growth Factor

IGF-1 LR3

Insulin-like Growth Factor 1, Long R3 variant — 83 amino acid analogue with extended half-life

Molecular Weight

9117 Da

Half-Life

20–30 hours

Storage

−20°C

Reconstitution

Acetic Acid

Typical Dose

20–100 mcg

Max Cycle

4 weeks

🔬 Overview

IGF-1 LR3 (Insulin-like Growth Factor 1, Long R3) is an 83 amino acid analogue of human IGF-1. The "LR3" designation refers to substitutions at the N-terminus (arginine replaces glutamic acid at position 3) and an added 13 amino acid extension peptide, collectively resulting in a significantly extended half-life compared to native IGF-1 (~20–30 hours vs ~15 minutes).

IGF-1 LR3 promotes cell proliferation, inhibits apoptosis, and stimulates glucose uptake. It binds IGF-1 receptors with similar affinity to native IGF-1 but has dramatically reduced binding to IGF binding proteins (IGFBPs), which is the primary reason for its extended half-life and increased potency.

Research applications include muscle hypertrophy studies, fat metabolism research, and investigation of anti-aging mechanisms mediated by the GH/IGF-1 axis.

💉 Dosing Protocol

⚠️ Cycle length must not exceed 4 weeks. Extended use leads to IGF-1 receptor downregulation, reducing efficacy and potentially disrupting endogenous IGF-1 signalling. Allow 4–6 weeks off between cycles.

Protocol	Dose	Frequency	Max Duration	Notes
Low	20–40 mcg	Once daily	4 weeks	Conservative research start
Standard	50–80 mcg	Once daily	4 weeks	Post-workout timing preferred in studies
High	100 mcg	Once daily	4 weeks	Upper range in animal research models

⚗️ Reconstitution Instructions

Important: IGF-1 LR3 requires acidic conditions for stability. Use 0.6% acetic acid (dilute acetic acid) rather than BAC water for initial reconstitution.

Prepare 0.6% acetic acid solution (or use pre-made peptide reconstitution solution)
Allow vial to reach room temperature
Add 1ml of 0.6% acetic acid to 1mg vial (resulting: 1000 mcg/ml)
Gently swirl — do not shake. Allow 5–10 minutes for full dissolution
For injection, dilute working dose in sterile saline (1:10) to reduce acidity at injection site
Store reconstituted vial at 2–8°C. Use within 14–21 days.

📍 Injection Sites

Intramuscular injection is preferred in research models as IGF-1 receptors are highly expressed in muscle tissue. Target muscle groups relevant to the research area. Sub-Q injection yields similar systemic effect but reduced local uptake.

🔗 Stack Compatibility

📚 Research Notes

Animal studies demonstrate IGF-1 LR3's superior potency over native IGF-1, with 2–3x greater anabolic effect in skeletal muscle due to extended receptor occupancy and reduced IGFBP binding. Studies have also shown fat oxidation effects and improved insulin sensitivity in short-term protocols.

⚠️ Disclaimer

IGF-1 LR3 is a research chemical not approved for human use. Strict 4-week cycle limits apply. Not medical advice.